1. Field
Embodiments disclosed herein generally relate to apparatus and methods for forming dielectric materials in high aspect ratio features. More particularly, embodiments of the present disclosure relate to controlling film thickness during spatial atomic layer deposition.
2. Description of the Related Art
As the device density on integrated circuits continues to increase, the size and distance between device structures continue to decrease. The decreased size results in increased high ratio of height to width in gaps in the structures and trenches between structures. To form integrated circuits, these high aspect ratio gaps and trenches are usually filled with dielectric materials like silicon nitride or silicon oxide to form electrical isolation. However, as aspect ratios of the gaps and trenches increase to 3:1 or above, it becomes difficult to fill the deep, narrow trenches without generating a blockage caused by a void or seam in the fill volume.
Cyclic deposition-etch, a process in which a substrate is alternatingly exposed to a deposition environment and an etching environment so that the substrate is processed by deposition-etch cycles, may be used to perform high aspect ratio gap fill. However, it is challenging to control film thickness for cyclic deposition-etch. Problems, for example, film thickness loss, i.e. the actual thickness of film is thinner than the target film thickness, may occur in deposition-etch cycles.
Therefore, there remains a need for methods to accurately control film thickness for high aspect ratio gap/trench fill.